The present invention relates to measuring devices, and more particularly, to apparatus for measuring a test liquid where a number of particles and an amount of pigment are measured.
To measure the number and the size of blood components (leukocytes, corpuscles, etc.) in a blood sample, the prior art mixes the blood sample with an electrically conducting liquid, and passes a fixed volume of the mixture through a minute hole. Electrodes on opposed sides of the minute hole pass an electric current through the mixture, and particularly through the hole. The electrical resistance of blood components is different from that of the electrolyte. As a result, when a particle of blood component passes through the minute hole, it partly blocks the minute hole, thereby changing the electrical resistance. A resulting pulse change in resistance is detected. The pulses are counted while the fixed quantity of the mixture is drawn through the minute hole to indicate the amount of blood component particles in the mixture. The amount of hemoglobin (red pigment) in the mixture is measured with a colorimeter.
When the number of leucocytes and the amount of hemoglobin is measured by conventional apparatus using a test mixture containing hemolysed (disassociated) red blood corpuscles, two separate liquid routes: one for measuring the number of leucocytes, the other for measuring the amount of hemoglobin.
Therefore, the liquid routes of conventional devices are complicated and expensive.
In addition, conventional devices require large amounts of test mixture and a large amount of liquid for cleanup between tests.
Furthermore, testing of blood components is frequently done in a series of tests of different blood samples. Purging of the equipment between tests is required. An automated technique for performing the tests and for performing the cleanup is desirable.